Trigger Hub

Trigger Hub is a simple service that listens for trigger events on HTTP clients and relays them to subscribed services that may not want to expose a dedicated port. In this way, triggers are pulled on the service instead of directly pushed by clients, which adds an extra layer of isolation.

Get started

Download the Linux binary or compile the project yourself:

go build -o build/triggerhub

Parameters

Parameters can be passed via command line of be defined in a config file

Command line

$ ./triggerhub -h
Trigger Hub is a simple service that listens for trigger events on HTTP clients and relays them to subscribed services that may not want to expose a dedicated port.

Usage:
  triggerhub [command]

Available Commands:
  help        Help about any command
  listen      Joins a Trigger Hub server
  serve       Start a dispatcher service

Flags:
      --config string   the config file to use
  -h, --help            help for triggerhub

Use "triggerhub [command] --help" for more information about a command.

Components

Dispatcher

The dispatcher is typically running on an external server (different to the target server handling actual work load). The dispatcher exposes an HTTP(s)/WS(s) endpoint that can be called by two actors:

• Web clients
  • Typically from a web browser
  • Requesting the invokation of an action on the target server
• The target server (listener)
  • Declares the supported action ID's that dispatcher clients may call
  • Listens to messages on the dispatcher's web socket

Config file

In dispatcher mode, the config file is optional. By default, triggerhub attempts to use config.yaml from the current directory. To use a config file on a different path:

$ triggerhub serve --config my-config.yaml

Copy config-dispatcher.template.yaml and adapt it to work for the data you want to back up.

token: "1234"    # Authentication token for target servers
port: 8443
tls: true
cert: /path/to/cert.pem   # not needed it tls = false
key: /path/to/key.pem     # not needed it tls = false

CLI parameters can override the port, cert, key and tls for easier testing.

Listener

Trigger Hub listeners are the hosts where the actual action is going to be executed. When running as a listener, no port is exposed and rather, a WS connection is made to the dispatcher.

Config file

The config file is required to run in listener mode. By default, triggerhub also tries to use config.yaml from the current directory. To use a config file on a different path:

$ triggerhub listen --config my-config.yaml

Copy config-listener.template.yaml and adapt it to work for the data you want to back up.

name: my-listener-name
dispatcher:
  url: wss://dispatcher-domain.com/ws
  token: "1234"   # Has to match the server's auth token
triggers:
- action: restart-service-1
  token: "1234567890123456789012345678901234567890"
  command: /home/user/scripts/restart.sh
- action: restart-service-2
  token: "0123456789012345678901234567890123456789"
  command: /home/user/scripts/restart.sh